THE SKIN, OR RIND, OF PLANTS. 7 J) 



most easily torn lengthwise, because it grows in this 

 manner ; but, when older, it is most easily torn across 

 because the cells ] (or what Guettard terms glands 2 ,) 

 stretch out in that direction. 



Professor Amici, by means of his powerful micro- 

 scope, has recently supported the opinion of Grew, 

 rinding the rind perfectly distinct from the layer be- 

 neath it, and composed of a simple layer of cells or 

 vessels 3 extremely variable in form in different species. 

 Were these cells continuous with those beneath, as 

 Malpighi and Michel maintain, they ought to have the 

 same form, which is not the case ; for in the pink and 

 other plants the cells of the rind are square, while 

 those beneath are in form of tubes placed perpendi- 

 cularly. 



There has, in some instances, been found a very 

 delicate, transparent, and apparently unorganised mem- 

 brane on the outside of the rind. Professor Henslow 

 observed this in the foxglove oak ; Adolphe Brongniart 

 in the leaf of the cabbage. 



Pores of the Rind. 



The pores 4 , or, as some term them, glands 5 , of the 

 rind, successively supposed and denied by authors, 

 have been incontestibly proved by Amici to be a sort 

 of minute bags, opening on the outside by an oval slit 



(1) In Latin, Lenticellulee. 

 (2) In Latin, Glandulce lenticular es, 



(3) Tn Latin, Vasa lymphatica. (4) In Latin, Stomata. 

 (5) In Latin, Glandules cictaneee. 



